After you get to Kakariko Village and talk to Impa, the Captured Memories quest will begin, then as you become more familiar with the landscapes of Hyrule you'll start to recognise locations from the photos on your Shiekah Slate.

Visiting them will give Link a flashback so that he can start piecing his hazy memory back together. While most of them are easy enough to reach, some of them can get a bit hairy. Sneaking around is the best way to get in and out of most places without causing a kerfuffle.

There are 12 memories in total, plus a bonus memory once you've reported back to Impa.